Why i think Oculus should be careful about its final FOV

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Libertine
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Why i think Oculus should be careful about its final FOV

Post by Libertine »

With all the news about the competition Oculus is going to be up against, especially Valve's with its 110 FOV, i've been thinking about the Rift a lot recently and something came to mind. I have not tried the Rift yet, so take this with a grain of salt. I have 2500 hours of 3D gaming now on a 46" 3DTV viewed from close up ( <1 meter) giving me a large FOV and i feel like i've learned a lot about the subtleties of stereo 3D. I really love the TV and I tried using a 27" 3D monitor to get out from under the HDMI resolution limitation, but the look of the 3D world was so much better on the big TV, even at 720p using a dim 1st gen 3DTV, that i passed on the 1080 monitor which had lightboost. However, could i have been somewhat accustomed to the larger screen, making the small one too hard to get used to in the amount of time i gave it? Perhaps, im not exactly sure.

The main reason I passed on the 27" was that the size of objects in the world looked so much bigger and real and thus impressive on the TV. The size of the 46" TV also allowed me to increase the in-game FOV in some games a tad while maintaining the relatively large size of the scene. But i also found that I sometimes liked playing games with the default narrow default FOV setting which increased the size of objects), like the console influenced Metro 2033, despite being a massive wide-FOV advocate, solely because of the realistic size the world took on, making it seem very large and real. Metro 2033 had many highly detailed 3D objects that were fascinating to see up close, as if they were real.

I have come to believe that the main aspect of amazing 3D is the depth cue matching the size cue. By size cue, i mean the way we use the size of something in our vision to determine its proximity, such as how a person's silhouette gets smaller as they get farther away or how train tracks appear to narrow into the distance.

On a "small" 27" monitor, the stereo effect can place the objects in the correct 3rd dimension location, but it does not match the size cue very well and large objects do not cover the FOV in your vision anywhere close to what they would in real life. Conversely, just for example, when watching Gravity and seeing a close up of Sandra Bullock on a massive IMAX screen in 3D, her head covers the FOV in your vision it would only if you were kissing her, yet the stereo depth cue says her head is on the screen making for a 3D experience that doesn't jive with what we know about experiencing the real world on a daily basis -greatly reducing the feeling of presence and immersion in my opinion.

I worry that the FOV may be underestimated in its importance by Oculus given that they were willing to go down in FOV for the DK2. The DK1 had a ton of positive response. But i wonder if any negative feelings towards the reduced FOV for of the DK2 were not voiced since it was just a sample and also a small % change thus perhaps hard to notice amid the possibility of so many other factors being at fault, not to mention the short review times many had with it. Also, how attuned is the average joe towards 3D dimensionality? I don't know.

The DK1 was not reviewed very well on the 3D Vision forums in comparison to 3D Vision, several times. Too be fair, a lot of the complaints were of course of the pixelation, motion clarity, etc. However, several times the amount of 3D depth available in the Rift was described as being less than the reviewers 3D Vision setup. Many of the regular members of that forum also use 3DTVs and projectors for 3D gaming giving a large FOV. Perhaps a 3D Vision forum member can summarize further as i missed a few in-depth discussions. Im assuming that a greater FOV in the Rift will allow for larger in-game FOV settings, but also keep object somewhat large. Overall, this makes me wonder how much better the Rift would be received and experienced with a wider FOV supporting large object size. For those that haven't tried it, as i understand it, the FOV is a diagonal measurement, which makes the Rift pretty narrow horizontally i guess?

The narrow FOV seen in some games of the last 7 years or so i assume was influenced by consoles, in that players sitting back on their couches need things to be bigger on the screen so they could see whats happening and the narrow FOV also fit that viewing distance. When building a game to support VR, i assume wide in-game FOVs will be used as a standard, which will reduce the object size the higher it is. Anyway, I hope Oculus reviews its final decision on FOV, testing different FOVs.

Any thoughts?

Edit: for a bit more clarity after seeing Dillip's response
Last edited by Libertine on Wed Jul 15, 2015 12:00 pm, edited 2 times in total.
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Dilip
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Re: Why i think Oculus should be careful about its final FOV

Post by Dilip »

Libertine wrote: I have come to believe that the main aspect of amazing 3D is the depth cue matching the size cue (as long as it matches our real life experience). By size cue, i mean the way we use the size of something in our vision to determine its proximity, like train tracks narrowing into the distance.On a "small" 27" monitor, the stereo effect places the objects in about the correct 3rd dimension location, but it does not match the size cue very well and large objects do not cover the FOV in your vision anywhere close to what they would in real life.
Exactly i mentioned many times this thing a "sense of depth" is not absolute but its rather a thing of perspective. you can't say some thing is big, if you don't have small things around. When you are in HMD that cut out you from external world you are only left things within CGI Space to compare. hence object placement and size of world that built inside CG space with scale matters. its how narrator or animator in case of movie placed objects across Z axis. If he planned near and far object with real world size and scale we could sense depth else all look as if shallow or lacking depth. you cant notice this thing at home as you have TV frame as reference so you can see scene playing on screen is at depth even though its shallow. So its on director or animator or developer how he developed the app or movie. One more interesting thing. "3D converted" movies are bound to look flat on HMD as there is no planned depth or anything as such while viewing in HMD. :)
Libertine wrote: I am assuming that a greater FOV in the Rift will allow for larger in-game FOV settings, but also keep object somewhat large. Overall, this makes me wonder how much better the Rift would be received and experienced with a wider FOV supporting large object size.
Your mistaking here, if you want large object they indeed has to be built large within virtual space as there will be no frame of TV or your room to compare and get subjective clue of sense. for VR things got to be made in real scale like you got to build 5.5/6 feet highted man model then only he will look proper at various distances withing the scene else either he will look tiny or giant depending on placement from your vision.

Libertine wrote:
When building a game to support VR, i assume wide in-game FOVs will be used as a standard, which will reduce the object size the higher it is. Anyway, I hope Oculus reviews its final decision on FOV, testing different FOVs.

Any thoughts?
FoV and Size perception in HMD are indeed independent. To make thigs look real in VR developers need to build them in real sizes like 6feet tall man and 80 feet tall dino and place them in real time spacing. It has less to do with FoV. If Fov is high you can see without moving your head else you got to move your head to see some thing that is larger than horizontal fov of your hmd. In short you got to develop everything in real scale to view them at real scale. miniatures don't fit the VR.
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Re: Why i think Oculus should be careful about its final FOV

Post by Mystify »

I think its far more important for the FOV of the screen to match the FOV that is rendered; One of the major advantages of VR over a 3d screen is that ability to line the size and depth cues to properly place you in the world and give you the right sense of scale/depth. The FOV is still important for givine you, well, a wide field of view and greater immersion, but a small FOV properly aligned will work better than a large FOV that is mismatched.
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Libertine
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Re: Why i think Oculus should be careful about its final FOV

Post by Libertine »

Let me define some terms before i reply so we don't get lost in a goofy semantics-based disagreement.

When i refer to the size depth cue, i am referring to how our human depth perception takes the space a object takes up in our real human FOV and uses it to help determine the distance of an object. For example:

Image

or

Image

When i refer to the in-game FOV i mean the FOV the game engine in rendering. Such as:

Image

or

Image


By "screen FOV" i meant that that the size of your screen and also the distance your viewing it from both additionally affect your view of , and thus your FOV of, the game world (on top of the in-game FOV setting). Sitting close to a small 17" monitor still yields a large screen FOV and sitting a long way from a 40" TV can yield a small screen FOV. The wider FOV of 90 in Skyrim in the picture above might look fine on a projector, but could look far too small on a 19" or 24" screen for some people's preferences, limiting the detail they can see on close by object and the feeling of presence those objects have. I've noticed my preference for FOV varies directly with the amount of interesting detail in the world, for example with Metro 2033, which is full of interesting detail, i actually like a small FOV, which makes objected look bigger and *feel* closer and i can see more details. As you might notice in the 3rd person view shot above, a larger FOV lets you see more of the world, but for me it also makes things less personal and intimate and objects close by have much less presence. In the case of Mass Effect, i used a cheat program to code in different FOV and used 4 different FOV settings that i varied with what was happening. For conversations i found that a huge FOV was much MUCH less engaging with a wide FOV.

Dilip wrote:Exactly i mentioned many times this thing a "sense of depth" is not absolute but its rather a thing of perspective. you can't say some thing is big, if you don't have small things around.
I disagree, you can, but i would say that it is much easier when you know what it is you are looking at and you are used to the 3D setup you are using. Jumping into a new 3D setup where the factors of 3D perception are all a little different requires a little bit of time to adjust in my experience. But once you are accustomed, the FOV the object takes up in your vision tells your brain it is a certain distance away from you, then the 3D tells your brain it is, well, *hopefully* the same distance away from you (as long as it is correct or at least impressive. I look up at ceilings and objects all the time without reference from anything else. Bear in mind, i'm not saying that reference objects don't help at all.

When you are in HMD that cut out you from external world you are only left things within CGI Space to compare. hence object placement and size of world that built inside CG space with scale matters. its how narrator or animator in case of movie placed objects across Z axis. If he planned near and far object with real world size and scale we could sense depth else all look as if shallow or lacking depth. you cant notice this thing at home as you have TV frame as reference so you can see scene playing on screen is at depth even though its shallow.
My 46" 3dtv sits only just under a meter away from me. The edges of the screen are beyond the frames of my glasses often. I sometimes pull the screen even closer and crank up the in-game FOV to 120-130 and doubt the TV frame comes into play significantly in either case.

Your mistaking here, if you want large object they indeed has to be built large within virtual space as there will be no frame of TV or your room to compare and get subjective clue of sense. for VR things got to be made in real scale like you got to build 5.5/6 feet highted man model then only he will look proper at various distances withing the scene else either he will look tiny or giant depending on placement from your vision.
Things are the proportionately the right size in games already. I think you're misunderstanding me. Have you ever played with in-game FOV settings? Are you familiar with how when you increase the FOV, things on the screen get squished together and smaller causing a fish-eye effect that increases as the FOV gets larger? If you have never done that, i can give you a quick example (or you can search google images for "FOV comparision") So for example I would guess almost everyone has zoomed in in a game using a rifle scope and seen that the objects get "bigger" in 2D. They are not actually bigger in physical size of course, but hopefully that illustrates the change in size (from lowering the FOV in that case) i am talking about. Not actual physical size. ( I added some info at the start of the post to clarify better what i mean)

Back in the heavy flight simulation days of Falcon 4.0 and even today, people would buy huge freznel lenses from medical supply outlets for their "large" 19" monitors, placed in front of the screen to make the screen appear much larger and cover more of their vision and make objects look much bigger and more life like. I have personally seen a 8" freznel lens make a 19" monitor look and "feel" like an IMAX theater, pretty cool effect, but thats another topic. In the case of an F-16 fighter plane, or almost anything since we use such small display relative to the objects we display on those screens, bigger on the screen and thus bigger in our FOV, means it is much closer to the real thing from a visual stand point, and thus, and this is the key: real and impressive. When you can then match the 3D settings to THAT, then, IMO, that is the holy grail of 3D and when the 3D/VR experience starts to look like a viewport to a holodeck.

FoV and Size perception in HMD are indeed independent. To make things look real in VR developers need to build them in real sizes like 6feet tall man and 80 feet tall dino and place them in real time spacing. It has less to do with FoV. If Fov is high you can see without moving your head else you got to move your head to see some thing that is larger than horizontal fov of your hmd. In short you got to develop everything in real scale to view them at real scale. miniatures don't fit the VR.
[/quote][/quote]

Again, 3D models in games are already built to real size proportions. :mrgreen: There is a lot of "unrealism" that has probably led to you thinking the game world objects are incorrect, such as viewing from a monitor which yields a FOV incorrect and smaller from the real world. There are also many subtler effects that i believe skew our perception of games world and lessen the feeling of immersion/presence, such as the fact that avatar movement speed is typically faster than a human sprint, such as in Halflife and Doom3 and others, not only that it is instantaneously fast, which is completely contrary to almost 100% of our human experience in the real world where the world usually passes us by at a slow walking pace. This is part of why i take the reigns of immersion into my own hands when i play games and i will often slow walk or even crouch (to slow down) with a weapon up at the ready when going into a dangerous area for example or when walking around in an impressive area, like the presidium in Mass Effect, which already has a realistic walking speed.

Image

To re-interate one more time with the F-16 example. If you have ever been to a military base or seen a fighter plane up close, im sure you have been very impressed with the size of it and being that close to it. This is the essence of what im talking about. You just can't get that feeling quite as well with a lower FOV. You need some screen FOV to allow a bump in in-game FOV to allow an F-16, or any object to increase in "size" and look and feel as real as it can.
Last edited by Libertine on Wed Jul 15, 2015 3:10 pm, edited 1 time in total.
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Re: Why i think Oculus should be careful about its final FOV

Post by Libertine »

Mystify wrote:I think its far more important for the FOV of the screen to match the FOV that is rendered; One of the major advantages of VR over a 3d screen is that ability to line the size and depth cues to properly place you in the world and give you the right sense of scale/depth. The FOV is still important for giving you, well, a wide field of view and greater immersion, but a small FOV properly aligned will work better than a large FOV that is mismatched.
I agree and hopefully my last post cleared up what i was getting at. Larger FOV are nice, sometimes, but they can lead to the fish-eye effect, which i asked Nvidia to eliminate it after i found out that there are 3rd party programs meant for surround screens that do this so they can increase the FOV without things stretching at the sides of screens (No response from Nvidia btw, shocking i know). Its a good idea since rendering is based on having point of view (one eye). Also, large field of views shrink things and pull them away from the viewer in a sense. You can see from the 3rd person screenshot above that the FOV has simply been increase, reducing the size of things, but the effect is that things look much farther away and as my experience has shown, makes the experience less immersive, makes NPC interactions less personal and lends less feeling of presence overall. (Hopefully im using the term presence the way other people currently understand it)

So, i agree, but im saying that is why we need larger screens or FOVs (screens positioned closer to the eye) so we can get more realistic looking objects and worlds, while retaining the proper game FOV for whatever displays we end up using.
Last edited by Libertine on Thu Jul 16, 2015 11:36 am, edited 1 time in total.
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Re: Why i think Oculus should be careful about its final FOV

Post by Dilip »

Thanks for example pictures many things i understood in a 'different' way in your earlier post, to which i had replied. i too loved ME1,2,3. ;)
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Re: Why i think Oculus should be careful about its final FOV

Post by WiredEarp »

Personally, I like as much FOV as possible, but at least DK1 standard would be good. DK2 I found a little too low FOV to give consistent presence (it does have acceptable immersion).

I suspect that theres a sweet spot between 90-110 FOV, where even small increases in FOV can give significantly more presence. Of course, I'm basing this on nothing but my experiences with DK1/DK2, but I had far more people I've demo'ed VR to rave over the DK1 than the DK2, despite everyone immediately saying that the DK1's resolution and blurring was annoying.

I sometimes hear people say they'd be happy to take a FOV loss for better resolution. I'd never want to do this personally - to me VR is best when you feel like you are really there.

CB gave me good presence though, and I dont know what FOV that was, so its entirely possible that it was just the content that made me feel immersed (and the fact that you could move around a limited amount, which I feel helps presence as well. If CV1 is at least as good FOV and resolution as CB, I think I'll be very happy with it, especially for a first generation.
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Re: Why i think Oculus should be careful about its final FOV

Post by rowanunderwood »

Inside the Oculus, FOV does not affect perceived size of virtual objects for two reasons. First, there are no real world objects in your peripheral vision to mess you up. Second, because Oculus has been working very hard to calibrate everything so that FOV and Depth match the real world. VR HMD's aren't like a 3d display where you need to tweak depth and convergence yourself due to varying screen sizes and distances. The only "tweak" you need to make is entering in your IPD. The only effect FOV in an HMD has is to make you feel more and more like you are wearing a scuba mask. However, even with DK2's fairly poor FOV, VR is still very immersive.

I have also messed around a ton with various 3d displays, including large TV's, monitors, and projectors, so I get where you are coming from. I also like sitting very close to a 3d display and cranking the FOV up to 90+. I much prefer getting closer to a high DPI display, than being a bit further away from a TV or projector because of the detail issue. The one exception to this is for my racing sim, where I simply have to have a place for the steering wheel :)
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